Walter appeared in the 1980 crime drama The Hunter (with LeVar Burton and Nicolas Coster), The Octagon (with Brian Tochi) and the telefilm High Noon, Part 2: The Return of Will Kane (with Michael Pataki). In 1981, Walter acted in the horror film The Hand (with VOY guest star Bruce McGill). Walter in 1982 received his first science fiction work in Timerider: The Adventure of Lyle Swann (with Ed Lauter). Next the same year was the film Honkytonk Man (costarring Jerry Hardin). 1983 found Walter appearing in his first short film The Horse Dealer's Daughter (with Philip Anglim). Walter then worked in 1984's comedy hit Repo Man (with Angelique Pettyjohn and Biff Yeager). Also that year was the fantasy adventure Conan the Destroyer (with TOS guest performer Jeff Corey).

His first work in 1993 was the crime-caper Public Enemy No. 2 (with Clint Howard and Tom Virtue). Next came the prison-escape comedy Amos & Andrew (costarring Brad Dourif and Jordan Lund), followed by the telefilm Basic Values: Sex, Shock & Censorship in the 90s (with Kenneth Mars). Walter also joined Charles Napier for the fourth time on film in the celebrated AIDS drama Philadelphia.

Walter got 1995 started appearing in the telefilm, Kidnapped: In the Line of Duty (with Carole Davis). In the martial-arts drama Fist of the North Star Walter rejoined Clint Howard on film. Accompanying Howard and Walter were Susan French and Malcolm McDowell.

In 2001, Walter reunited with Carole Davis and Cari Shayne in the comedy Jack the Dog. Following this comedy, Walter switched to drama appearing in The Man From Elysian Fields (with "Rascals" costar Rosalind Chao and Sherman Howard). That year Walter rejoined Chao in the sci-fi drama Impostor (along with Golden Brooks, Brian Brophy, Maury Sterling, and Clarence Williams III). Walter rounded out the year in the marijuana-themed comedy How High (opposite Lark Voorhies).

Early in 2003, Walter rejoined Carole Davis in the drama Manhood. Another reunion took place when Walter worked with Louis Giambalvo again in the comedy film Duplex, which also had in the cast Jenette Goldstein, Michelle Krusiec, and Walter's Ferengi actor colleague Wallace Shawn. Walter rejoined Richard Riehle that year in the telefilm Monster Makers. 2004 had Walter rejoining Jude Ciccolella, Charles Napier, and Dean Stockwell in the 21st century remake of the thriller The Manchurian Candidate (which also costarred Miguel Ferrer). Walter went from that drama to the telefilm comedy Family Plan (with Kate Vernon). Next Walter lent his voice to the video game 50 Cent: Bulletproof (2005, with Tommy "Tiny" Lister, Jr.). The only work in 2006 connecting Walter to another Trek actor was the holiday-themed The Year Without a Santa Claus (with Michael McKean). 2007 was more connected starting with Man in the Chair (opposite Ellen Geer, George Murdock, and Christopher Plummer), Noble Son (with Kirk Baily), The Death & Life of Bobby Z (with Keith Carradine), and finally that year Walter rejoined Richard Riehle in Wasting Away (with Colby French). 2008 saw Walter in Just Add Water (with Tracy Middendorf), and the horror film Dark Reel (with Tony Todd). Walter concluded the decade reuniting with Bruce McGill in the baseball movie The Perfect Game (2009, with fellow TNG guest actor John Cothran, Jr.

Walter's work this decade has included rejoining Larry Ceder twice, first in Midnight Son and Alyce (with Megan Gallagher) for 2011.

Walter's first work on a television series was on the cop show Starsky & Hutch (starring David Soul) in "Dandruff" (1978, with Rene Auberjonois), then on the radio sitcom WKRP In Cincinnati (with Vincent Schiavelli) in "The Contest Nobody Could Win". A year later, Walter was on Vega$ in "Mixed Blessings" (with David Huddleston). He was on the sitcom Taxi starring Christopher Lloyd as a panhandler in "A Grand Gesture" (1983) with Schiavelli as well. Walter was next on the crime drama Hunter in "Pen Pals" (1984, with James Whitmore, Jr.), then on Amazing Stories in "The Wedding Ring" (1985). Next for Walter was the helicopter action series Airwolf in "Wildfire" (1986, alongside Lance LeGault, Ken Olandt, and Gregory Sierra).

It would be a pair of police series that would give work to Walter in 2002, first on The Division (starring James Avery) in "Forgive Me, Father" (with Jeffrey Dean Morgan) and then Boomtown (starring Neal McDonough) in "Reelin' in the Years" (with April Grace and Tommy Hinkley). On Reno 911, Walter guested in "Department Investigation" (2004, with Lisa LoCicero). A near half-decade went by until Walter won a guest role on the short-lived police comedy Raines (starring Linda Park). Walter then rejoined Geoffrey Blake on Monk in "Mr. Monk & the Miracle" (2008). Walter repeated the once a year work on the Philadelphia-set police drama Cold Case (co-produced by Roxann Dawson) in "The Crossing" (2009) and finally on the ghostly crime drama Medium (executive produced by Kelsey Grammer) in "Bring Your Daughter to Work Day" (2010).

Walter's first lead role was as Frog Rothchild, Jr. on the short-lived western series Best of the West, which only ran a single season from 1981 to 1982. Christopher Lloyd was in the series premiere, "The Calico Kid Returns" (1981) as the title role and "The Calico Kid Goes to School" (1982), "They're Hanging Parker Tillman" (1981, with Jonathan Banks), "Frog's First Gunfight" (with Barbara Babcock), and "The Pretty Prisoner" (1982, with Ted Gehring).

In the '90s outright, Walter won a role as Blinky Watts in the mini-series On the Air (1992, with Miguel Ferrer, Mel Johnson, Jr., David Lander, and Richard Riehle). In 1993, Walter worked with Mary Crosby's niece Denise Crosby on the comedy-western The Adventures of Brisco County, Jr. as the man with the rhyming first and last names Phil Swill in "No Man's Land" (with Judson Scott) and "Mail Order Brides" (with Jeremy Roberts).

Starting in 1996, Walter played his most recognized television role, that of Peter Spellman (primarily known as Angel) on the San Francisco-set crime-comedy series Nash Bridges. Angel acted as such on the behalf of the title character played by Don Johnson. Walter began this role in the show's second season episode "Hit Parade" (with Robin Sachs) and "25 Hours of Christmas" (with Cristine Rose, in addition to Mary Mara, who was a lead on the show at the time). The fourth season in 1998 saw Walter appearing in "Firestorm" (with Daniel Roebuck and Sean Whalen). Walter appeared in 2000's fifth season finale "Jackpot" (with Stephen Lee and Tzi Ma). In the sixth and final season, Cress Williams joined the lead cast. With Williams, Walter appeared in "Land Pirates" (also in 2000, with Michael Bailey Smith) and in 2001, "Blood Bots" (with Caroline Lagerfelt and Tommy "Tiny" Lister, Jr.) and "Quack Fever" (with Williams alone).

Walter's signature episode was the fourth season "Angel of Mercy" (1999, appearing with Edward Laurence Albert), as the episode covered his character's back-story and discovery of a long-lost brother.